let a = [1,2,3];
// Object.prototype.toString.call()
console.log(Object.prototype.toString.call(a).slice(8,-1) === 'Array');

// 原型链
console.log(a.__proto__ === Array.prototype);


// Array.isArray
console.log(Array.isArray(a));
  
// instanceof
console.log(a instanceof Array);

// Array.prototype.isPrototypeOf

console.log(Array.prototype.isPrototypeOf(a),'11');
